1. Field of the Invention
The invention pertains to stack gas emissions monitoring systems using moveable gas differential pressure and temperature measurement devices whose readings are electronically recorded for analysis.
2. Description of the Related Art
Environmental standards require that gaseous emissions from smokestacks, particularly large stacks such as used by utility companies in the generation of electric power, meet predetermined emission standards. Periodic testing of the gaseous stack emissions is required and conducted, and reports are regularly submitted to the appropriate government environmental agencies.
In the past, gaseous stack emissions were determined by locating differential pressure and temperature measurement devices temporarily within the smokestack at predetermined locations, and the measurements were manually recorded. Such recording was accomplished by one individual placing the measurement devices into the flue gas stream within the smokestack, and another individual nearby recording the readings from analog instruments connected to the output of the measurement devices.
Usually, the stack gases are monitored at more than one horizontal location within the smokestack, and several ports, or openings in the stack wall to facilitate such measurements, are arranged along a horizontal plane around the circumference of the smokestack. This traditional system of flue gas flow measurement is expensive and time consuming (requiring two operators), and is subject to errors in the reading of the analog meters, data recording at the test location, and subsequent data transcription to computer spreadsheets for the final calculations and report.
A variety of sophisticated electronic systems and devices have been utilized in the analysis of emissions from various sources, and such devices are illustrated in U.S. Pat. Nos. 4,561,288, 4,786,472, 5,206,818, 5,415,025, 5,479,359, and 5,526,280. However, devices such as shown in these patents are not specifically designed for the measurement of volumetric flow of stack gas emissions.